简介:众所周知,电池化成后正极板活性物质的主要物相是PbO2(α-PbO2+β-PbO2),负极板活性物质主要物相是海绵状金属Pb。无论通过何种铅膏配比、和膏工艺、何种固化工艺生产的生极板,经化成后的正极板或负极板活性物质,都是具有相同主物相组成的具有一定活性的多孔性开放型体系,唯有的差异是活性物质的聚集体型结构有所不同。极板铅膏的物相组成、聚集体状态严重影响极板的孔体系结构及活性物质参与反应的真实比表面积,从而对电池的充放电性能产生直接的影响。文章利用极板总孔体积专用检测装置,结合极板铅膏的XRD物相分析,对极板的总孔体积以及极板的一致性问题进行分析和探讨。
简介:大直径人工挖孔扩底桩由于优点显著,近年来在我国多、高层建筑中得到广泛的应用。本文根据国家有关规范(规程)并结合工程实例.对人工控孔扩底桩的优点、构造要求及设计计算进行阐述。
简介:Inthepresentwork,computationalsimulationswasmadeusingANSYSCFXtopredicttheimprovementsinfilmcoolingperformancewithdualtrench.Dual-trenchconfigurationconsistsoftwotrenchestogether,onewidertrenchandtheotherisnarrowtrenchthatextrudedfromthewiderone.Severalblowingratiosintherange(0.5:5)wereinvestigated.Thepitch-to-diameterratioof2.775isused.Byusingthedualtrenchconfiguration,thecoolantjetimpactedthetrenchwalltwotimesallowingincreasingthespreadingofcoolantlaterallyinthetrench,reducingjetvelocityandjetcompletelycoveredonthesurface.Theresultsindicatethatthisconfigurationincreasedadiabaticeffectivenessasblowingratioincreased.Thespatiallyaveragedadiabaticeffectivenessreached57.6%foratM=2.Noobservedfilmblow-offatallblowingratios.Theadiabaticfilmeffectivenessofdualtrenchcaseoutperformedthenarrowtrenchcase,laidbackfan-shapedhole,fan-shapedholeandcylinderholeatdifferentblowingratios.